Because economies (for example, regional economies, national economies, global economies, and cross-sections thereof) can be very complicated, economists tend to be interested in generating economic indicators that help quantify and/or predict behaviors of the economies.
As a first example, consumer spending trends often provide insight into the behavior of an economy. When consumers start purchasing more of one type of product, or less of another type of product, that information may be used by businesses and/or government entities to make informed business and/or economic policy decisions. Similarly, growth or decline in particular economy or economic sector may help businesses and/or government entities to make informed business and/or economic policy decisions.
As a second example, businesses are often interested in their employees' productivity levels. High productivity helps propel business growth, while low productivity can hinder business growth. However, businesses often struggle to correctly identify and implement effective investments in worker productivity.
As a third example, businesses and government entities are often interested in the balance of import and export levels between different political entities, such as cities, counties, states, or countries. A large imbalance one way or the other may provide insight into the effectiveness of business and/or economic policy decisions.
The aforementioned examples are only a subset of the various economic indicators in which businesses and government entities may be interested. Many different types of economic indicators exist that may help businesses and/or government entities make informed business and/or economic policy decisions.